Energy broadly means the capacity of something, a person, an animal or a
physical system to do work and produce change.
Used in science to describe how much potential a physical system has to
Sources of Energy.
Conventional sources of
sources of energy
Non Conventional Energy sources:
Those energy sources which are renewable
and ecologically safe.
such as solar energy, wind energy, biomass
energy, ocean energy (tidal energy, wave
energy, ocean thermal energy), geothermal
energy, nuclear energy etc.
Some sources of energy are non renewable
like coal, petroleum and natural gas.
About 16% of global final energy consumption comes from
renewable, with 10% coming from traditional biomass, which
is mainly used for heating, and 3.4% from hydroelectricity.
New renewable (small hydro, modern biomass, wind, solar,
geothermal, and biofuels) accounted for another 3% and are
growing very rapidly.
The share of renewable in electricity generation is around
19%, with 16% of global electricity coming from
hydroelectricity and 3% from new renewable.
Wind energy : Airflows can be used to run wind turbines.
Wind energy is used in wind mills which converts the kinetic energy of
the wind into mechanical or electrical energy.
The kinetic energy of wind can be used to do mechanical work like lifting
water from wells or grinding grains in flour mills.
A single wind mill produces only a small amount of electricity.
large number of wind mills in a large area are coupled together to
produce more electricity in wind energy farms.
The minimum wind speed required is15km/hr.
At present Wind power potential of India is 1020 MW
Largest wind farm is near Kanyakumari in Tamilnadu generate 380 MW
Advantages : It is a renewable source of energy.
It does not cause pollution.
The recurring cost is less.
Once the wind turbine is built the
energy it produces does not cause green
Disadvantages : Wind is not available at all times.
It requires a large area of land.
A minimum wind speed of 15 km/h is
Solar energy : energy obtained from the sun in
the form of heat and light.
Energy derived in the form of solar
The solar energy received by the
near earth space is approximately
1.4 kilojoules/second known as
The heat energy is used in solar
heating devices like solar cooker,
solar water heater, solar furnaces
etc. The light energy is used in solar
Various technologies in which solar
energy can be used:-
Solar hot water systems
Solar air heaters
Solar desalination systems
Solar cooker : The box type solar cooker has
an insulated box painted black
It is covered by a glass plate
which allows heat to enter inside
but does not allow heat to
It has a mirror to reflect more
sunlight into the box.
The food to be cooked is kept in
containers inside the box
It can produce a temperature of
100° to 140°.
Solar water heater :A solar water heater has an
insulated box painted black inside
with a system of copper tubes.
It is covered with a glass plate
which allows heat to enter inside
but does not allow heat to escape
When water flows through the
copper tube it absorbs heat and
Device which converts solar
energy into electrical energy.
Solar cells are made from
semi conductors like silicon,
germanium, gallium etc.
A single solar cell produces a
voltage of about 0.5 to 1 V
and produces about 0.7 W
several solar cells are
arranged in a solar panel to
produce more electricity.
Advantages of Solar Energy
After initial investment, all the electricity you produce is
It is abundant.
It is everlasting.
It is available almost everywhere.
It is free from political barriers.
Incentives and rebates from governments and utility
companies offset the initial investment.
Reduce or completely eliminate your electric bill.
Cost of solar panels are decreasing while efficiency is
Hydro power plants : In hydro power plants water from rivers
are stored by constructing dams.
Micro hydro systems are hydroelectric
power installations that typically produce
up to 100 kW of power.
They are often used in water rich areas as
a remote-area power supply (RAPS).
Run-of-the-river hydroelectricity systems
derive kinetic energy from rivers and
oceans without using a dam.
E.g: Grand Coulee Dam in Washington
State and the Akosombo Dam in Ghana.
Advantages of Hydro power energy: Flowing water is a renewable source of energy.
The electricity produced does not cause pollution.
The water stored in dams can also be used to control floods and for
Once a dam is constructed, electricity can be produced at a
Often large dams become tourist attractions in their own right.
Disadvantages : The initial cost is high.
Large areas of land gets submerged and the decomposition of
vegetation produces methane gas which is a green house gas.
It causes displacement of people from large areas of land.
Biogas plant : Mixture of gases containing methane, carbon dioxide, hydrogen and
It is produced by anaerobic degradation of animal waste.
Anaerobic degradation means break down of organic matter by bacteria in
the absence of oxygen.
The biogas plant has a large underground tank made of bricks and
The lower part is the digester and the upper part has a dome with a gas
Animal dung is mixed with water in the mixing tank and the slurry is sent
into the digester.
The gas is taken out through the gas outlet and used for heating and
The slurry left behind is rich in nitrogen and phosphorus and is used as
manure for crops.
From cattle dung alone we can produce biogas of a magnitude of 22,500
A sixty cubic feet gobar gas plant can serve the needs of one average
This gas contains 55 – 70 percent methane, which is inflammable and it is
generally used as cooking gas and for generation of electricity.
Tidal energy : Produced by gravitational forces of sun and moon.
Produced by making the use of water movement from a high tide to a low
The high tide to a low tide refers to the rise and fall of water in the ocean.
A difference of several meters is required between the high and low tide.
Ocean waves and tides can be made to turn a turbine and generate
Areas where rivers flow into the sea experience waves and tides and
electricity can be generated there. It has much potential.
As you know we have a large coastline and major river
systems in our country, electricity can be generated on a large
scale from waves and tides.
The periodic rise and fall of sea level due to gravitational
attraction of the moon causes tides.
A Tidal barrage is constructed at a narrow opening between
the land and sea.
The movement of water during high tide and low tide can be
used to rotate the turbines of generators to produce
Tidal power site In india :-gulf of cambay, gulf of Kutch and the
sunder bans delta.
Geothermal energy : It means the energy harnessed from the hot rocks present inside the earth .
High temperature, high pressure steam fields exit below the earth’s surface
in many places.
At the core, temperatures may reach over 9,000 degrees Fahrenheit.
This heat comes from the fission of radioactive material naturally present in
The deeper regions of the earth’s crust is very hot. This heat melts rocks and
The magma moves up and collects below at some places called Hot spots.
The underground water in contact with hot spot gets heated into steam at
By drilling holes into hot spots the steam coming out can be used to rotate
turbines of generators to produce electricity.
There are 46 hydrothermal areas in India where the water
temperature normally exceeds 150 degree centigrade.
Electricity can be generated from these hot springs.
In many places the the hot water comes out of the ground
through cracks in the form of Natural geysers:E.g. Manikaran,
Kullu and sohana, Haryana.
Earth's geothermal energy originates from the original
formation of the planet (20%) and from radioactive decay of
Advantages of Geothermal Energy
Significant Cost Saving : Geothermal energy generally involves low running
costs since it saves 80% costs over fossil fuels and no fuel is used to generate the
Reduce Reliance on Fossil Fuels : Dependence on fossil fuels decreases with
the increase in the use of geothermal energy. With the sky-rocketing prices of
oil, many countries are pushing companies to adopt these clean sources of
Environmental Benefits : helped in reducing global warming and pollution ,
does not create any pollution as it releases some gases from deep within the
earth which are not very harmful to the environment.
Direct Use : Since ancient times, people having been using this source of energy
for taking bath, heating homes, preparing food and today this is also used for
direct heating of homes and offices.
Job Creation and Economic Benefits .
Biofuel:Biofuels include a wide range of fuels which are derived
The term covers solid biomass, liquid fuels and
Liquid biofuels include bioalcohols, such as bioethanol, and
oils, such as biodiesel.
Gaseous biofuels include biogas, landfill gas and synthetic
Bioethanol is an alcohol made by fermenting the sugar
components of plant materials and it is made mostly from
sugar and starch crops.
Trees and grasses, are also used as feedstock for ethanol
production. Ethanol can be used as a fuel for vehicles in its
Bioethanol is widely used in the USA and in
Biodiesel is made from vegetable oils , animal
fats or recycled greases.
Biodiesel can be used as a fuel for vehicles in its
pure form, usually used as a diesel additive to
reduce levels of particulates, carbon monoxide,
and hydrocarbons from diesel-powered
Biodiesel is produced from oils or fats
using trans esterification and is the most
common biofuel in Europe.
Biofuels provided 2.7% of the world's
transport fuel in 2010.
Advantages of Bio-diesel
It is an agriculture based fuel substitute.
It can be made from both vegetable oil and animal fats.
It can be used without major modifications in engines.
It does not need separate infrastructure for storage and
Handling bio-diesel is safer.
It’s combustion emits less carbon monoxide, sulphates,
unburnt hydrocarbons and particulate matters, thus
reduces air pollution.
Nuclear energy :Nuclear energy is the energy is the energy released during
some mass is converted into energy very large amount of energy
is produced during nuclear reactions.
Nuclear reactions are of two types:Nuclear fission :- the nucleus of a heavy atom like uranium,
plutonium, etc. splits into smaller nuclei with the release of a
large amount of energy.
It is used to make atom bombs and to produce electricity.
Nuclear fission :In a nuclear power plant the heat energy produced by a
Fission chain reaction is used to produce steam which rotates
the turbines of generators to produce electricity.
NUCLEAR FUSION:A nuclear reaction in which small nuclei fuse together to form a
heavier nucleus with the release of a very large amount of
The energy of sun is produced by the fusion of hydrogen nuclei
to form helium nucleus.
It is also used to make the hydrogen bomb.
Advantages of nuclear energy :-
It produces a very large amount of energy per unit mass
than any other source of energy.
If safety measures are taken, it is more environment
friendly than fossil fuels.
The cost of a nuclear reactor is very high.
The availability of nuclear fuel is limited.
Nuclear reactors produce harmful nuclear wastes which is
difficult to dispose.
Conservation and Use of Natural Resources
Minimize exploitation of non-renewable energy resources.
Emphasis on use of renewable sources of energy.
Stop wastage of energy.
Creating awareness among people regarding wise and
judicious use of energy.
More use of bio-mass based energy
Project on which we work:We contributed towards
our work by educating
1. How to make
surroundings clean and
2. How to retain it for so